It is often desirable to print features on a plurality of sheets and then accurately position those sheets relative to one another with respect to those features. Printing is used herein in the very broadest sense to include any kind of marking or depositing. For example, the printing of adhesive in lines on sheets of material to create a honeycomb structure. In that application sheets are printed with parallel spaced lines of glue and then are stacked with the lines of alternate sheets aligned with each other and the intermediate sheets aligned with each other but shifted with respect to the alternate sheet lines. The stack is heated under pressure so the glue adheres. Then the stack is expanded to create the honeycomb structure. One approach to this fabrication technique is to use a rotogravure web press to print the glue lines on the material and then cut the web into sheets. The sheets are positioned by hand using the printed features as references to align the alternate and intermediate lines. One problem with this approach is that the rotogravure process in web form creates tension and tension gradients in the web during the printing process. However, after cutting the web into sheets there is no tension in the sheets. Thus, since the sheets are often elastic the position of the features may vary slightly from sheet to sheet and accurate alignment is difficult. Further, stacking and alignment is difficult to do by eye with high accuracy. And when sheet placement is done by reference to previously placed sheets inaccurate positioning can occur cumulatively.
Another approach to sheeting and stacking pre-printed material is to locate the glue lines and to sheet with respect to those glue lines. Then use the cut edge to align the sheet. A problem with this approach is that the error in adhesive line alignment is the error in locating the glue lines plus the error in aligning the edges.